1. Field of the Invention
This invention relates, generally, to auto inflators. More particularly, it relates to an auto inflator design that reduces the pressure on the dissolvable element.
2. Description of the Prior Art
The CO.sub.2 in a CO.sub.2 cartridge of the type used to rapidly inflate inflatable articles is typically under about eight hundred pounds of pressure, and about sixty to eighty pounds of pressure are required to puncture the membrane that seals the cartridge. In the known auto inflator designs, a dissolvable element is positioned between a spring-loaded pin and the membrane; when the element becomes wet, it dissolves and the pin penetrates the membrane. The pin, therefore, is directly driven into the membrane. In some designs, the pin is released into the membrane. In none of the earlier designs is the lanyard pulled automatically.
There are several drawbacks to the above-described auto inflators. First of all, a substantial bias means is required to provide the requisite sixty to eighty pounds of pressure, and the dissolvable element must be strong as well to withstand that pressure for long periods of time.
Moreover, the known auto inflators are overly sensitive to the presence of moisture, and often inflate when they should not. More particularly, they often inflate if they are simply splashed or rained upon; they have even been known to inflate under conditions of high humidity. An unwanted and unnecessary inflation wastes the cartridge and requires labor to retrieve and install another one.
Another problem in the industry is the problem of discharged cartridges that are connected to the inflator manifold of the object to be inflated. Since a cartridge may be used only once, an individual wearing a life vest that relies for its inflation upon a discharged cartridge is obviously in jeopardy. All of the known auto inflators, however, have no means for quickly determining whether or not a cartridge attached to an auto inflator has been used or not. The only known method to check the status of the cartridge is to unscrew it from the inflator and visually inspect the membrane for a puncture.
The prior art, when considered as a whole by those of ordinary skill therein, includes no teachings or suggestions as to how an auto inflator could be re-designed so that its dissolvable element would not be required to withstand sixty to eighty pounds of pressure. Moreover, no teachings exist concerning how to make an inflator that automatically pulls the lanyard as distinguished from directly driving or releasing the puncture pin. Nor does the art suggest how the unwanted inflations caused by the presence of insubstantial amounts of moisture could be avoided, or how empty cartridges could be detected without requiring removal of the cartridge from the inflator.